Business Energy, Jan./Feb. 2014, by Daniel P. Duffy
http://www.businessenergy.net/DE/Articles/A_Penny_Saved__24310.aspx

"A properly operating heating, ventilating, and air-conditioning (HVAC) system is a lot like a football lineman. When it is running perfectly, you don’t even know it is there. Recent advances in efficiency, operating controls, durability, and “smart” applications can make your HVAC system even more unnoticeable."